1. Field of the Invention
The present invention relates to a power semiconductor module of resin-sealed type and a method of manufacturing the same.
2. Description of the Background Art
Recently, advances have been made which allow power semiconductor modules to, for example, have a larger capacity, a more compact size and a higher frequency. The heat generation density of a semiconductor element becomes higher along with this, which requires high cooling performance.
In a conventional cooling structure, a cooler is mounted onto one outer surface of a power semiconductor module, and the heat generated by the semiconductor element inside the module is transferred to the cooler and is dissipated. In this case, it is possible to improve cooling performance by reducing a thermal resistance of a member constituting a heat transfer path ranging from the semiconductor element to the cooler. In view of an increase in capacity of a module as descried above, however, such a measure against thermal resistance is limited.
As a solution to such a problem, there is the technology of Japanese Patent Application Laid-Open No. 2009-212302 (hereinafter, referred to as Patent Document 1). According to a semiconductor module of Patent Document 1, heat dissipating plates are respectively placed in thermal contact with both main surfaces of a semiconductor element, and each of the heat dissipating plates is electrically connected to an electrode of the semiconductor element. The heat dissipating plate is molded integrally with the semiconductor element with a molding resin.
In the semiconductor module of Patent Document 1, one heat dissipating plate is bonded to one surface of the semiconductor element, and the other heat dissipating plate is bonded to the other surface of the semiconductor element via a spacer. Solder is used for bonding of components.
This configuration requires a plurality of spacers and a plurality of heat dissipating plates in a case of a semiconductor module containing a plurality of semiconductor elements, resulting in a cost increase. Further, an increase in part count complicates manufacturing, also leading to a cost increase.
That is to say, the configuration of Patent Document 1 is unsuitable for a semiconductor module containing a plurality of semiconductor elements.